STRESS CHANGE HISTORY OF THE 2000 TOTTORI-KEN-SEIBU EARTHQUAKE AND NEAR-FIELD STRONG MOTION

Abstract

The stress change history of the 2000 Tottori-ken-seibu earthquake is determined using the strong motion records. The result shows large stress drop in the upper central part of the fault. Negative stress drop is observed at the NW and SE sides of the fault at the depth of between 5 and 10 km. The slip distributions agree with those obtained from kinematic models. The stress-time histories in the high stress drop zones show predominantly monotonic stress drop. The result indicates that relatively high peak velocities observed at the stations near the fault are due to the high stress drop and the directivity effect. The ground motion inferred from the obtained stress change shows high peak velocity around the source area.